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What is Black Walnut?

C. Ausbrooks
C. Ausbrooks

The black walnut, also known as the American walnut, is a deciduous tree native to the central and eastern parts of the United States. The black walnut tree was introduced to Europe in the early 17th century, and is currently cultivated in North America and Europe. The term may also be used to describe the fruit of the tree, which drops to the ground in the late fall. These trees can reach heights of up to 150 feet (45.7 meters), thriving in small groves in mixed forest lands.

Black walnut bark is deeply furrowed, dark gray to black in color, and has a rough diamond pattern. The compound leaves grow alternately, and can reach up to 24 inches (61 centimeters), each with 10 to 24 smaller leaflets growing up to 3.5 inches (8.9 centimeters) in length. Black walnut trees flower in the late spring, with males producing single-stemmed catkins, and females producing short flower spikes near branch ends.

A black walnut infusion can help treat colic.
A black walnut infusion can help treat colic.

The walnut fruits, also known as simply black walnuts, are round and hard with a thick green husk. A hard, furrowed nut is found inside the husk, containing an edible nut meat, which is harvested commercially for food. Black walnuts are used to make black walnut ice cream and the popular flavoring, black walnut extract.

Black walnut wood has been heavily harvested to make fine furniture, gunstocks and flooring. Today, the wood is used primarily to make veneer due to a decrease in availability. The husk of the black walnut is used to make dye and wood stain. Early American settlers used the dye to color hair, but it is used in modern times for basket-making and other wood craft projects.

Black walnut can be used to make wood stain.
Black walnut can be used to make wood stain.

Native Americans used the bark, leaves and fruit of the tree for medicinal purposes, and some traditional herbalists still employ these remedies for the treatment of various ailments. The inner bark of the tree is made into a laxative tea, or chewed to reduce toothache pain. The husk of the black walnut is made into a poultice for skin inflammation, or applied to treat ringworm. A black walnut infusion, made of the leaves and nuts of the tree, is used to treat stomach cramps and colic.

Cramps might be treated with an infusion of black walnut.
Cramps might be treated with an infusion of black walnut.

The leaves, twigs and fruits of this walnut contain juglone, a chemical which inhibits the growth of other plants near the tree. This is nature's way of ensuring all the beneficial nutrients in the soil are available to the black walnut. However, some plants can withstand the chemical, including goldenrod and fescue grass, making it difficult for the tree to survive. These invading plants may be removed with herbicide if necessary, to keep the tree healthy and thriving.

Discussion Comments

Wisedly33

Black walnuts do have a strange, astringent taste. They don't taste much like English walnuts at all. I'm not crazy about them, except in ice cream. I prefer pistachio ice cream as far as a nut ice cream goes.

I do love the look of black walnut, wood, though. My mother has an ancient dining room table that's black walnut and it is beautiful. It's been well kept over the years, and it's really a beautiful piece of furniture.

Scrbblchick

Never heard of black walnut leaves being used to treat ringworm, but I sure wish the neighbor's trees were black walnuts instead of those stupid chestnuts.

Black walnuts can be eaten, and black walnut ice cream is a popular flavor. My dad loved it. You have to be careful cracking the nuts, though. They have this stuff on them that will dye your hands greenish black if you don't wear gloves when you crack the nuts. They're tough to crack, too, and you need a hammer to open them up. I always wear my gardening gloves, and they work just fine.

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    • A black walnut infusion can help treat colic.
      By: kmrep
      A black walnut infusion can help treat colic.
    • Black walnut can be used to make wood stain.
      By: minicel73
      Black walnut can be used to make wood stain.
    • Cramps might be treated with an infusion of black walnut.
      By: Johan Larson
      Cramps might be treated with an infusion of black walnut.
    • The inner bark of the black walnut is sometimes chewed to relieve toothache.
      By: Dessie
      The inner bark of the black walnut is sometimes chewed to relieve toothache.
    • Parents of infants with colic should talk to their pediatricians before giving black walnut leaves to their babies.
      By: Galina Barskaya
      Parents of infants with colic should talk to their pediatricians before giving black walnut leaves to their babies.
    • Black walnut tea can be made by steeping the tree's leaves in boiling hot water.
      By: Fisher Photostudio
      Black walnut tea can be made by steeping the tree's leaves in boiling hot water.
    • Black walnut leaves are often used to treat ringworm.
      By: schankz
      Black walnut leaves are often used to treat ringworm.